Liquid crystalline monomers and mixtures of monomers in combination with photoinitiators can exhibit nematic and smectic mesophases. Under ultraviolet ("UV") irradiation these nematic and smectic mesophases can undergo rapid photopolymerization, in the presence of UV-photoinitiators, to freeze-in the structure and orientation (alignment) of the nematic and smectic mesophases into a polymer matrix. The films and fibers derived from this process have valuable optical and physical properties and are useful as packaging films, laminated films, polarizing films, optical information storage films, optical fibers, etc.
Using conventional techniques, the mesophase is aligned on a substrate using standard aligning techniques for low molecular weight liquid crystals, such as rubbing the surface of a glass substrate or a polymer coating on a substrate, so that all of the molecules are oriented in one direction. After irradiation with UV light, the resulting polymer has the orientation of the monomeric mesophase film frozen into the polymer matrix.
For instance, Japanese 62 70,406 describes the polymerization of nematic monomers in the liquid crystalline state in the presence of a polymerization initiator with ultraviolet radiation. The molecules are oriented by a support or coating on a support, which support or coating has been previously rubbed with cloth in the orientation direction.
The instant inventors have discovered that orientation of monomeric liquid crystals can be selectively controlled to produce aligned multi-oriented monomeric mesophases and that these aligned multi-oriented mesophases can be photopolymerized to give films and fibers with multiple orientations frozen-in to polymeric matrices.